Carbon monoxide is an odorless, colorless and toxic gas and is dangerous because it is impossible to see, taste or smell the toxic fumes. At lower levels of exposure, CO causes mild effects that are often mistaken for the flu.

These symptoms include headaches, dizziness, disorientation, nausea and fatigue. The effects of CO exposure can vary greatly from person to person depending on age, overall health and the concentration and length of exposure.